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Sprout/sprout/math/llround.hpp
2012-07-05 08:03:32 +09:00

55 lines
1.5 KiB
C++

#ifndef SPROUT_MATH_LLROUND_HPP
#define SPROUT_MATH_LLROUND_HPP
#include <limits>
#include <type_traits>
#include <stdexcept>
#include <sprout/config.hpp>
#include <sprout/math/detail/config.hpp>
#include <sprout/type_traits/enabler_if.hpp>
namespace sprout {
namespace math {
namespace detail {
template<typename FloatType>
inline SPROUT_CONSTEXPR long long
llround_impl_positive(FloatType x, long long x0) {
return x - x0 < FloatType(0.5) ? x0
: x0 + 1
;
}
template<typename FloatType>
inline SPROUT_CONSTEXPR long long
llround_impl_nagative(FloatType x, long long x0) {
return x0 - x < FloatType(0.5) ? x0
: x0 - 1
;
}
template<
typename FloatType,
typename sprout::enabler_if<std::is_floating_point<FloatType>::value>::type = sprout::enabler
>
inline SPROUT_CONSTEXPR long long
llround(FloatType x) {
return x < 0 ? sprout::math::detail::llround_impl_nagative(x, static_cast<long long>(x))
: sprout::math::detail::llround_impl_positive(x, static_cast<long long>(x))
;
}
template<
typename IntType,
typename sprout::enabler_if<std::is_integral<IntType>::value>::type = sprout::enabler
>
inline SPROUT_CONSTEXPR long long
llround(IntType x) {
return static_cast<long long>(x);
}
} // namespacedetailmath
using NS_SPROUT_MATH_DETAIL::llround;
} // namespace math
using sprout::math::llround;
} // namespace sprout
#endif // #ifndef SPROUT_MATH_LLROUND_HPP